Islamabad: Rescuers were Sunday set to search the smouldering remains of Islamabad’s Marriott Hotel for survivors following a huge truck bombing which left at least 60 people dead and 200 injured.

There were fears more dead would be found in the wreckage of the hotel, a popular gathering place for foreigners and Pakistan’s elite which was almost totally destroyed by t he attack at dinner time on Saturday.

Officials said they were worried the building, which burned through night after after the blast ruptured a gas pipeline, would collapse. A security official said many people leapt to their deaths from upper floors.

The bombing came shortly after new President Asif Ali Zardari, who faces a desperate struggle against Al-Qaeda and Taliban militants, delivered his inaugural address to parliament only a few hundred metres away.

It was one of the deadliest attacks in an increasingly bloody campaign by Islamic militants in Pakistan, a vital ally in the US-led “war on terror," and presented Zardari with a major challenge just days after he took office.

“Terrorism is a cancer in Pakistan, we are determined, God willing, we will rid the country of this cancer," Zardari said in a televised address to the nation. “We will not be deterred by these cowards," he said.

“Pakistanis are brave and fearless people. They are not afraid of death," said Zardari, the widower of late opposition leader Benazir Bhutto who was assassinated by suspected Islamic militants in December last year.

The attack appeared to be timed to cause the maximum number of casualties, coming as the hotel was thronged with families holding their evening meal to break the daily Ramadan fast.

Eyewitness Mohammad Jamil said the truck exploded just outside the heavily-secured hotel’s gates. He said the force of the blast sent the truck flying into the air, and knocked him over onto the street.

“For a few seconds I was in shock and did not know what had happened. Then I remembered the deafening noise," Jalil said.

The blast, so powerful it was heard for miles, blew an enormous crater in the ground and destroyed the outside wall of the compound. Buildings several kilometres away had windows blown out from the impact.

Army called in

The government ordered in the army to try to clear away the debris. But senior police officer Saqib Sultan said rescuers were unable to search for victims deep inside the building which was still burning early Sunday.

“The death toll is 60 and it may go up," said a senior security official who declined to be named.

Hospital officials said a US national was among the dead. The security official said women, children and an unknown number of foreigners had died.

“The government had received word two days ago of a possible attack near the parliamentary offices," interior ministry official Rehman Malik said.

IntelCenter, a US organisation that tracks militants, said an Al-Qaeda leader who claimed responsibility for a previous bombing in Pakistan threatened new attacks in a video this month to mark the anniversary of 11 September.

Earlier attacks

The Marriott was attacked previously in 2004 and 2007. Nearly 1,300 people have been killed this year alone in a wave of militant violence across Pakistan.

As Al-Qaeda and Taliban militants have tried to establish a safe-haven in the northern tribal areas, attacks have spread to the capital more often.

US President George W. Bush condemned the attack, which he said: “Is a reminder of the ongoing threat faced by Pakistan, the United States, and all those who stand against violent extremism."

In Britain, Foreign Secretary David Miliband said the “disgraceful" bombing had strengthened the resolve to fight militancy.

Although a close anti-terror US ally since 9/11, critics have repeatedly insisted that elements of Pakistan’s powerful intelligence service give clandestine backing to Islamist militants.

Zardari will meet US President George W. Bush in the United States next week for the first time since he took the oath of office on 9 September.

The Bush administration has accused Taliban Islamic militants and Al-Qaeda followers of using the unruly border areas as bases from which to direct a growing deadly insurgency in neighbouring Afghanistan.

Meanwhile strains have emerged between Islamabad and Washington over strikes by US forces on Pakistani tribal areas, carried out by US forces operating in Afghanistan.